Which performance class of high-visibility safety apparel is NOT acceptable for workers in the TTC zone?

The correct answer identifies that Class 4 high-visibility safety apparel is not acceptable for workers in the Traffic Control (TTC) zone due to its specific intended use and visibility requirements outlined in safety standards.

Class 4 is not a recognized performance class for high-visibility safety apparel as defined by The American National Standards Institute (ANSI)/International Safety Equipment Association (ISEA) standards. The acceptable classes for use in TTC zones are Class 1, Class 2, and Class 3. Each of these classes has specific criteria for color, design, and reflectivity, ensuring that workers are easily seen and significantly enhancing their safety in environments where they could be exposed to vehicular traffic.

Classes 1, 2, and 3 provide varying levels of visibility as the classes increase, with Class 3 offering the highest level of visibility for more hazardous situations. As such, it's critical for supervisors and workers to adhere to the appropriate standards for high-visibility apparel in order to reduce the risk of accidents and enhance overall safety in traffic control environments.